[Alan Anderson]

That's a single-pole double-throw switch. If you look closely, you'll see that the pins are marked COM 1, NC 2, and NO 3. Pin 1 is the common terminal, pin 2 is the normally closed contact, and pin 3 is the normally open contact. When the switch is not being activated, pins 1 and 2 are connected together. When the switch is being activated, pins 1 and 3 are connected together.

The Robot Controller digital inputs have an internal pullup resistor to +5 volts on the signal pin, so all you need to do in order to make them work is provide a switched path between the ground and signal pins. That's pins 1 and 2 on the switch if you want the value to be 1 when the switch is activated, or pins 1 and 3 on the switch if you want the value to be 0. Leave the unused pin unconnected, and do not connect +5 to the switch at all.